What happens in a By-me system in case of power supply failure?

The By-me home automation system turns off. when the control unit is connected to the burglar alarm system BUS, the control unit and devices will remain powered thanks to the presence of the backup unit until the batteries reach the minimum voltage level of that can support operation (after which the backup unit disconnects the batteries to save them from being fully discharged, once the minimum operating voltage of the system has been breached). It is therefore good practice to predispose a second power source which can be connected in an emergency.